The Internet is the new TV. At least that is what U.S. advertisers seem to be saying.

Spending on digital video advertising in the U.S. is expected to rise 41.4% in 2013 and by nearly 40% in 2014, to reach $5.7 billion, according to eMarketer. Now data from the Interactive Advertising Bureau suggest a good portion of that increased spending may represent money redirected from TV.

Seventy percent of U.S. senior ad-buying executives told the IAB they would likely move TV dollars to digital video in the next 12 months. Twenty percent of respondents were undecided, while 10% said they were unlikely or very unlikely to shift TV dollars to digital.

This doesn’t mean the overall budget for TV ads will necessarily fall. But it suggests growth in that spending could slow.

The shift underscores why Big Tech firms are vying to distribute TV over the Internet. And it may help push more media companies into their arms, following in the footsteps of Viacom, which reached a preliminary agreement with Sony last week. For TV, the web is closing in.

Update: An earlier version of this post said eMarketer expects spending on digital advertising to rise 41.4% in 2013 and by nearly 40% in 2014 to reach $5.7 billion. Those estimates apply to digital video advertising.